The objective of this project is a better understanding of the structure, replication, and assembly of influenza virus. The ultrastructure of the virion and subviral components and the biosynthesis of viral macromolecules will be studied. The polypeptides of the virion will be isolated and their location in the virion and functions determined. Biophysical studies will be directed toward defining further the organization of the virion, the viral membrane, and the nucleocapsid, and the interactions among the structural components of the virion, particularly the proteins and lipid. These studies will involve the use of electron microscopy, electron spin-resonance, and fluorescence spectroscopy. The assembly of the viral membrane will be investigated by identifying viral envelope proteins in cell fractions, and analyzing any migration between cell compartments that may occur. Ultrastructural studies using labeled antisera will be designed to determine the mode of assembly of the viral membrane at the cell surface. The nuclear phase in viral replication will be analyzed by determining the location of virus-specific structures in the nucleus, and investigating their properties and functions. The effects of actinomycin D on the migration of viral macromolecules within the cell will be studied. Viral RNA polymerase will be identified in the nucleus and cytoplasm, and the components associated with this activity in these sites and in the virion will be compared. Structural components of ribosomes will be compared in normal and infected cells.